pure
淳 centers on the idea of purity in a natural, unadulterated sense—something genuine, sincere, and free from corruption or pretense.
淳 combines 氵 (water) with 享, which likely contributes the sound and the idea of something rich or full. The water radical suggests purity or clarity, as in clean water.
Water (氵) beside 享: imagine a clear, pure spring feeding a rich, full vessel. The water is so clean it represents untainted sincerity.
For ジュン, picture a pure, clear stream in June: June -> ジュン, and the water is perfectly pure.